The present invention relates to a navigation system and, more particularly, to a portable navigation apparatus comprising a main navigation apparatus which is fixed to a vehicle and a sub-navigation apparatus which is detachable from the vehicle.
Conventionally, portable navigation apparatuses configured to be detachable from a vehicle are known (refer to Japanese Patent Application Laid-Open No. 4-238218). In such a portable navigation apparatus, a display, a storage unit for storing variety of information, a navigation unit which calculates and obtains current position data and controls to display the current position of a vehicle together with map information provided from the storage unit on the display, a connection cable to connect an on-vehicle battery as a vehicle electric source, and a connector for the aforementioned cable are integrally configured in a container. The portable navigation apparatus can be used on a vehicle by connecting to the battery via the connection cable and the connector. Further, the portable navigation apparatus can be also used in another vehicle by disconnecting the connection cable from the battery of the vehicle to which it is connected currently, attaching the apparatus to the other vehicle, and connecting the connector to the battery of the other vehicle. Thus, the portable navigation apparatus is not fixed to a specific vehicle, and if it is not needed in a vehicle on which the navigation apparatus is currently attached, it can be moved and used in another vehicle, thereby, improving a utilization efficiency of the navigation apparatus.